Call-distributing telephone system.



H. P. CLAN SEN. GALL DISTRIBUTING TELEPHONE SYSTEM. APPLICATION FILEDJUNE 26, 1911.

Patented Mar. 16, 1915.

8 SHEETS-SHEET 1.

W1 JZEEEEZ/Z; H ZEVEEZHTUR- W Em" HUGE]? H. P. ULAUSEN. CALLDISTRIBUTING TELEPHONE SYSTEM.

AP PLIGATION FILED JUNE 26, 1911.

1,131,91 1. 1 Patented M31216, 1915.

3 SHEETS-SHEET 2.

H. P. CLAUSEN.

CALL DISTRIBUTING TELEPHONE SYSTEM.-

Patehted Mar. 16, 1915.

' 3 SHEBTS-SHE ET 3.

APPLICATION FILED JUNE 26/1911.

\Q/IIHE 5E5 [m/En fur only of installation. 'matically distributingincoming calls can UNITED STATES PATEN FFT@@ HENRY P. CLAUSEN, OFROCHESTER, NE VK. YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERNELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

CALL-DISTRIBUTING TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Mar. 16, 19115.

Application filed June as, 1911. Serial No. 635,296.

- To all whom it may concern:

Be it known that I, HENRY-P. CLAUsEN, a citizen of the United States,and resident of Rochester, county of Monroe, State of New York, haveinvented certain new and useful Improvements in Call-DistributingTelephone Systems, of which the fOllOWlHgJS a specification; v

My invention relates to call-distr buting telephone systems. In systemsof this class the incoming telephone calls are automatically distributedbefore idle telephone operators, so that the work of. the variousoperators is equalized, and so that the subscribers calls receive promptattention.

The object of my invention is to combine a call-distributing system witha regular common battery multiple manual system so lines thoseoriginating, say, five calls an hour or over-and connect them withautomatic distributer switches at the central oflice, leavingv the otherlines to terminate before operators in the usual way.

My system further provides means for preventing a call which originateson one of the distributed lines from appearing before an-operator who atthat time has one or more unanswered manual calls upon each division ofher section of the switchboard.

My system further provides means for preventing a call which originatesupon a distributed line from appearing before an operator who at thattime hasone un-.

answered distributed call upon each division of her section oftheswitchboard; in

other words, my system provides means for distributing, before theregular manual operators who are not burdened with unan swered calls ofeither class, the calls originating upon the'busiest lines in theexchange. v

One advantage of this system is the econ- Switches for autonot beinstalled at as low a cost as the apparatus associated with the line ofa regular multiple switchboard, and it is, therefore, extravagant andunnecessary to provide distributing switches for lines which originatei111 average of less than, say, five calls per lOLll'.

Another advantage of my system is the incentive which it furnishes theoperators for answering calls promptly. Each operator may be in chargeof 100 regular incoming lines and may have, in addition to those, 10call-distributing trunks. The operators may be paid their regularsalaries for handling the regular lines and may be paid piece-work ratesin accordance with the number of calls answered upon theircalldistributing trunks. It will be seen that no call will appear uponone of these call-distributing trunks when more than one unanswered callappears before the operator, either among her regular lines or among thecall-distributing trunks. The operator will therefore endeavor to answerall calls promptly so that her call distributing trunks will at alltimes be free to receive the calls of distributed lines. This results inprompt attention and quick service.

Another feature of my invention is the applicationof the call counter,making the piece rate above described possible. i

Other features of my invention will be pointed out in the followingdescription and claims.

My invention is illustrated in the accompanying drawings, in which allapparatus is shown in its normal or unactuated condition.

Figure 1 illustrates two linesterminating in automatic distributingswitches and one regular telephone line. Fig. 2 illustrates theanswering and multiple jacks of the regular telephone line, the multiplejacks for the distributed telephone lines, and the operators calldistributing trunk circuits to which these lines have access, also thecircuits and apparatus for barring calls on the call-distributing trunkwhen unanswered calls appear before the operator, and Fig.3 illustratesthe operators cord circuit for use with either the regular manual or thecalldistributed trunks, and also illustrates a regular subscribers linewith which the cords may be connected.

Subscribers stations 1, 2, 8 and 4 are each provided with the regularcommon battery equipment, consisting of a condenser 5 and ringer 6 in abridge between the telephone line conductors 7 and 8, and of thetransmitters 9 and receivers 10 in a bridge maintained normally open bythe contacts of the switch-hooks 11. The limb 7 of subscribers lineextends from substa tion 1 to the central ofiice and thence throughcontacts 12 and 13 of cut-off relay 14 and through the coil 15 of linerelay 16 to conductor 17, which extends to the live pole of battery A.The limb 8 of this subscribers line extends to the central oifice andthence through contacts 18 and 19 of cutoff relay 14 and the coil 20 ofcut-in relay 21,"to ground. The removal of the receiver at subscribersstation 1 closesthe circuit in this path and actuates relays 16 and 21.The actuation of relay 21 closes its contacts 22 and 23 and theactuation of relay 16 closes its contacts 24 and 25. A circuit is thuscompleted from battery conductor 17, through the interrupter 27, thewinding of motor magnet 28, conductor 29, contacts 25 and 24 of linerelay 16, contacts and 31 of cut-off relay 14, contacts 23 and 22 ofcut-in relay 21, private conductor 33, se ment 34, brush 35 and busycontacts 36, 37 and 38 of the distributing switch to ground, these busycontacts being grounded, as will be hereinafter described. The currentin this path causes the operation of the motor magnet 28 and thestep-by-step 'movement of the brushes of the distributing switch untilthe brush 35 arrives upon the nongrounded contact 39. At this timecurrent flows from battery conductor 17, through interrupter 27, thecoil 28 of the motor magnet, conductor 29, contacts 25 and 24 of'linerelay 16, contacts 30 and 31 of cut- 31 of cut-ofi relay 14 and alocking circuit is completed which maintains the actuation of relays 14,16 and 21. This circuit may be traced as follows: from batteryconductor- 17 through the coil 48 of cut-ofi' relay 14,

the coil 49 of cut-in relay 21, conductor 50,

contacts 51 and 31 of cut-ofi' relay 14, conductor 42, contacts 43 and44 and coil 45 of line relay 16, conductor 46 and the coil 47 of cut-oilrelay 14, to ground. The actuation of cutofl relay 14 closes itscontacts contacts 54 and 55, and 56 and57 of cut-in relay 21 to thesegments 58 and'59 of the. 'distributer switch. The segment 58 is nowconnected, through brush 60 and contact 61, with conductor 62 whichconnects with earth through contacts 63 and 64 of trunk cut-off relay65, Fig. 2. The segment 59 is now connected through brush 67, contact68, conductor 69, contacts 70 and 71 of trunk cut-oil? relay and thecoil of trunk relay 72 through conductor 73 to battery conductor 17. Thecurrent in this latter path and through the transmitter and receiver atthe calling subscribers station actuates trunk relay 72. The actuationof relay 72 closes its contacts 74 and 75, thus connecting the groundpole of battery through contacts 76 and 77 of relay 65, private conduc-'tor 78, contacts 39, brush 35, segment 34, conductor 33, contacts 22 and23 of cut-in relay 21, conductor 42 and contacts 43 and 44 of line relay16 to'the coil-45 of that relay. The ground connection on the coil 45through coil 48 of relay 14, coil 49 of relay 21, conductor 50,contacts51 and 31 01 relay 14, contacts 23 and 22 of relay 21, conductor33, segment 34, brush- 35 and contact 39 of the distributer switch,conductor 78,

contacts 77 and 76 of trunk cut-01f relay 65 and contacts 74 and 75 oftrunk relay 72, to ground. The closure of contact-s 7 5 and 74 of relay72 also places a ground connection upon all of the other privateconductors extending to this particular operators group. This circuitmay be traced from ground,

through contacts 75 and 740i trunk relay 72, conductor 80, contacts 81and 82 of key 83,.common conductor 84, contacts 82 and 81 of keys, 83associated with other trunks, contacts 76 and 77 and private conductors78 of all other trunks in this articular group not at that time busy,and t e private contacts 39.0f all of these trunks on their particulardistributer switches. This places an artificially busyconditionupon thecontacts of the distributer switches to prevent other calls from beingdistributed before this particular operator until the call arising fromsubscribers station 1 has been answered. The actuation of trunk relay 72also closes contacts 86 and 87, completing a circuit from batteryconductor 17, through the winding of the pilot relay 88, conductor 89,trunk l1ne lam 90 and contacts 87 and 86 of trunk relay 2, to ground.The current in this path lights the; trunk lamp 90- to indicate to theoperator that a call has 18 and 52, and 12 and 53; extending thearisenupon this particular trunk line. The,

operator, observing the display of lamp 10E" relay 65, to ground? The''current in this path actuates'relays94 and 652 Theactua tion'of relay65 severs the circuitof-trunk relay 7 2 and contacts 70"-and 71= ofrelay'fifi and severs the j ground connectionof condoctor-"62 atcontacts-63 and-64 of=relaly 65':

' The 1 actuatiorr'of" relay "65 also= closes"'its"- calls 'to'bereceived" in this particular sec: tion' of the "switchboard; Smcc'it isde-'- 30" contacts 99' and 77 and'interrupts contacts 77 and 76. Theground"-connectionis thuS maintained upon private conductor 78,"

- through contacts 99 and 77. I The interrup tion of the "circuitthrough trunk relay72' permits that relay to fall 'back' 'andopen;thecircuit of the-trunk lamp 90, thus eifacingfi that signal. At the sam'e'tin'ie thegtound connection is 'severed'from conductor 80,"- thusfreeing the 'comm'om conductor 84' from its ground connection andpennitting -other sirable to record the number of calls ap pearingbefore this'parti-cular operator, therelay 72 is provided-=withfanadditional" pair of 'contacts'-'101"and 102, which, when" closed,complete'a-circuit'ifrom batter goonductor 17, through the winding 103 orelay 104,"conductor105 and contacts 102 and 101 v of relay 72,toground; The currentun this relay path 'actuates' relay 104;-closingits contacts 106'and 107 in the'ci-rcuit orthecall counter" 108, thusrecording one call." Itwould not" be desirable to permit the callingsubscriber to record a large'number of calls by moving-- his receiverhook up and down rapidly and thereb energizing and deenergizing trunk l2and consequently the coil 1030frelay 1041 Therefore a locking coil 1091sprovided for relay 104," which maintains-the actuationofthat relay, ifthe subscriberhangs' up his receiver, over-the circuit which may betraced from battery conductqnl7, Fig; 1, through the coil 48"of 'cutofirelay' 14, the coil 49 of cut inrelay '21,'-con-ductor 50, contacts-51 and- 3l-of cut oif' relay 14, contacts 23 and 22 0f cut-inre'la'y21', private conductor segment 34, brush- 35 'arid'contact "39 of thedistributer'switch, privateconduct'or 78, contacts"77 and 76"of trunkcut-oil relay 65,"conductor 80", contacts 81 and 82' of key 83, commonconductor 84, coil 109, and-contacts 110'and'11'1 of relay 104, toground. It will be seenytlierefore', that relay 104, afteroncebeingactuated, will remain actuated whether"relay'72 is actuated ornot, until'the opei'ator has conneeted with the jack of the callingtrunkand h'as actuated trunlvcut ofi relay 65-;- When this relay isactuated the circuit throughthe locking coil109, of relay 104.

is interrupted at=contacts 76 and 77 of relay 65,- and relay'104'there'fore resumes its nor mal 'position', -ready torecord a secondcall whenithi's--operator s position'is again se-' lected. Theresistanceof the 'coil- 109' of relay 104 is preferably madequite low, so

that during the actuationof-that relay the ground connection throughcontacts lll and 110, the coil 109' of relay'104and conductor 84"willbesufiicientto bar other'calls from coming in on" any of the trunksex--tendingto this particular group,

When' a subscriber removes his receiver and then replaces it, and thus'actuates relay 104, the operator s attention will be called'by'theflashingef the trunk lamp 90,

and the "operator can then depress her callbarring key' 114 to completeashunt about the coil 109of -'relay' 104 and again release that'rela'y.If the operator doesnotnotice the=flashirig of thela-mp 90, relay 104will be released-" when any regular manual subscriber'makes'a calleinthis particular operators' 'divisi'on by the actuation of pilot relay115 which will be described later, and

thegclosing of contacts 116 and 117 of that relay, thus connecting ashunt about the coil 109' of-relay .104. The connection of theoperators' plug'92 withthe jack 93 completes a circuit from the livepole of battery 'A- through supervisory relay 94, sleeve conductor '95,sleeve contact-96 of the plug and ring contact 118 of the jack 93,conductor'69, contact-68, brush 67 and segment 59'of the' distributerswitch, contacts 57 and 56 of cut-in relay'21, contacts 53 and 12 of cutofi relay 14, line conductor 7, transmitter 9, receiver 10, switch-hook11, line conductor 8, contacts 18 and 52 of cut-off relay 14, contacts54 and 55 of cut-in relay '21, segment 58,brush 60 and contact 61 of thedistributor switch, conductor 62, the tip contacts 119 and 120 of thejack and plug, conductor 121 and the coil of tip supervisory relay 122to the ground pole of battery A. The current in this path increases themagnetization of supervisory relay 94 and actuates supervisory relay122, thus preventing the answering supervisory lamp 123 from beingdisplayed at this time.

The operator now obtains the number of the de- .slred subscribers linein the usual Way and visory relay 125, conductor 126, contacts 127.

operators ringing key, sleeve contacts 129 and 130 of the plug and jackand the COll of cut-ofi relay 131 to the ground pole ofbattery A. Thecurrent in this path actuates cut-off relay 131, moving its contacts totheir abnormal positions and thus separating the limbs 7 and 8 of thetelephone line from their normal connection with battery and ground. Theactuation of relay 125 closes its contacts 132 and 133, thus completingthe circuit of the calling supervisory signal 134 to display thatsignal. The operator now depresses herringing keyand connects thealternating current generator 138 with the tip of the calling plug. Thecurrent therefore passes over the tip contacts 139 and 140 of thecalling plug and jack, line conductor 8, ringer 6, condenser 5, lineconductor 7, ring contact 141 of the jack and contact 129' of the plug,contacts 128 and 142 of the operators ringingkey and the non-inductiveresistance 143 to battery conductor 17 and thence back to the generator138. The current in this path passes through condenser 5 and actuatesthe bell at the desired subscribers station. When the desired subscriberanswers his call a circuit is completed from the live pole of battery A,through the coil of superand 128 of the operators ringing key, sleevecontact 129 and ring contact 141 of the plug and jack, line conductor 7,transmitter 9, receiver 10, contacts of switch-hook 11, line conductor8, tip contacts 140 and 139 of the jack and plug, series contacts 144and 145 of the operators ringing key, contacts 146 and 147 of theoperators listening key, conductor 148 and the coil of tip supervisoryrelay 149, to the ground pole of battery A. The current in this pathactuates the tip supervisory relay 149 and effaces the supervisorysignal 134. The calling and called subscribers are now in conversationand all signals are in their unactuated condition at the central oflice.lVhen these subscribers replace their receivers upon their respectiveswitch-hooks the circuits through tip supervisory relays 122 and 149 aresevered and the supervisory lamps 134 and 123 are displayed, the displayof these signals indicating tothe operator that the conver-.

sation has been terminated and that the plugs should be removed from thejacks with which they are connected.

The circuit of the answering supervisory signal 123 is carriedthrough'conductor 151 and the coil of pilot relay 152. This relay hasnormally open contacts 153 and 154, adapted when closed to ground thecommon conductor 84, which, as formerly explained, prevents calls frombeing received on the trunk lines appearing in this particular group,the purpose of this being to make the operator'prompt in removing'itheplugs from the jacks at the termination of a conversation. Theundistributed lines with which this same cord circuit may be connectedfor answering regular manual calls may be of the type just described andshown.

.throughconductor 159- and the coil of pilot relay 115 so that theactuation of this line lamp, or the lamp of any other line terminatingat this particular position in, the switchboard, will cause theactuation of relay 115. The actuation of this relay closes its contacts116 and 117, placing ground 1 upon the common conductor 84 and thuspreventing any of the trunk lines extending to-this particular operatorsgroup being selected by any of the'distributer switches. Relay 115 alsohas normally open contacts 160 and 161, which complete the circuit ofthe pilot lamp 162, which is displayed whenever a call, either regularor distributed, appears in this particular operators group.

It it to be understood that the calling plug 124 may be inserted intothe multiple jack of one of the lines provided with a distributerswitch. When this is .done the operation of the cord circuit and of therelays associated therewith is exactly the same as when the cord isconnected with a regular manual line, The cut-ofi relay 14 is pulled upin the same manner as cut-off relay 131 .of the manual line. The circuitfor actuating this cut-01f relay 14 may be traced from the live pole ofbattery A to the coil of supervisory relay 125, sleeve conductor 126,contacts 127 and 128 of the operators ringing key, sleeve contact 129and ring contact 170 of the plug and jack, conductor 171, contacts 56and 172 of cut-in relay 21,

conductor 46 and the coil 47 of cut-ofi relay they already haveunanswered calls before preferably equipped with the apparatus shown anddescribed herein. While I do not desire to limit my invention to twogroups, this number will be found to be convenient as in this manner theoperator may have a distributed call in each group simultaneously andthus she may, during the busiest period, have one call ahead of her atall timesthat is, a call may appear in one group while she is answeringa call in the other group, and a second call may appearin the secondgroup while she is answering the call in the first group. If only onegroup per operator is used a slight loss of time will occur betweencalls, and if more than two groups are used the subscribers will berequired to wait too long before their calls can be attended to.

It will be seen that my system is applicable to extensions to manualexchanges which are now equipped with regular multiple circuits. In aregular manual multiple system, when a large number of lines terminatebefore an operator, it frequently occurs that a rush of calls will notonly use up all of the operators available cord circuits, but will, inaddition, so overwork the operator that subscribers will be required towait longer for replies to their calls than could be expected of themost patient subscriber. With my system, however, the number of regularsubscribers lines terminating before any operator is kept to such aminimum that the operator can answer the calls during the rush periods,not only without using up all of her cord circuits, but without makingit necessary for subscribers to wait a considerable length of timebefore their calls are answered. It seldom happens that the rush periodoccurs before all operators simultaneously, and with my system anoperator who is rushed by reason of a large number of calls on herregular manual subscribers lines does not receive any of the calls whichcome in upon the distributed lines until all of the manual calls havebeen answered. If, then, the operators cord circuits :are almostexhausted she may depress her total barring "button and thus prevent anydistributed calls, from appearing in her position, these calls beinggiven to operators who are at that time caught up with their calls andwho have available cord circuits.

It sometimes happens that an operator is unavoidably drawn into anextended conversation with the subscriber, which may last severalseconds, and during this time it is convenient for the operator todepress her total barring button 114 and thus prevent calls from beingdistributed to-her position at this time. I

-It will be found that with this system the operators loads in calls perhour will be nearly equalized and, therefore, that the number ofoperators for answering a given number of calls can be considerablyreduced since all of these operators will be worked up to substantiallythe limit of their speed at all times, and there will never be operatorswho have scarcely any calls to answer while other operators are eatlyrushed.

While I haveshown an described my invention with respect to certaindefinite and well-known manual systems, it is to be understood that itmay be applied to other systems and that the specific circuitarrangements may be largely altered without in any way departing fromthe spirit'or scope of my invention.

I claim:

1. In a telephone system, the combination with an operators connectivemeans controlled by a connecting operator, of a telephone line extendingfrom a sub-station to the central office and permanently terminating ina connective means at sald connecting operators position, a secondtelephone line extending from a sub-station to the central ofiice andautomatic distributing means for extending it to any one of a pluralityof operators positions, andnieans to prevent said line from beingextended to said operators position when an unanswered call exists uponthe other line.

2. In a telephone system, the combination with an operators connectivemeans con trolled by a connecting operator, of a telephone lineextending from a sub-station to the central office and permanentlyterminating in contacts at said connecting operators position, a secondtelephone line extending from a sub-station to the central oflice andmeans for automatically extending it to any one of a plurality ofoperators positions, said means acting to extend said line to anotheroperators position when an unanswered call exists on the first telephoneline.

3. In a telephone system, the combination with telephone linesextendingfrom 'sub scribers stations to operators positions at a central office,other telephone lines extending from subscribers stations to thecentral.

4. In a telephone system, the combination with undistributed telephonelines and trunks leading to the same operators group, other telephonelines and means for variously connecting them, with said trunks, andmeans for preventing the use of said trunks .when an unanswered callexists upon an undistributed telephone line extending to said group.

.5. In a telephone system, the combination with undistributed telephonelines and trunksleading to the same operators group, other telephonelines and means to connect them with said trunks, and means forpreventing the use of said trunks when an unanswered call exists upon anundistributed telephone line or upon a trunk extending to said group. r4

6. In a telephone system, the combination with a plurality of telephonelines, of a switch for each of said lines, multiple contacts for saidswitches connected with trunks, and a plurality of operators groups towhich said trunks extend, motor-mechanism for said switches adapted torotate the same in one direction only, an undistributed telephone lineextending to one'of said operators groups, and means to cause theactuation of said motor-mechanism to rotate said switches to prevent theconnection of any one ofthe first telephone lines with the trunksextending to said group when an un- I 'answeredcall exists on saidundistributed telephoneline.

7. In a telephone system, the combination with a plurality of telephonelines, of answering jacks permanently associated with certain lines,trunk jacks and means to automaticallyassociate them with certain lines,

said answering jacks and trunk jacks being in the same group, and-meansto prevent the trunk jacks from being automatically associated with oneof said lines when an unanswered call appears upon one of the answeringjacks in said group.

8. In a telephone system, the combination with a plurality of telephonelines, of a plurality of groups of line terminals at the central oflicepermanently associated with said lines, a second plurality of telephonelines and a second plurality of terminals in said groups, and means toautomatically connect one of the second plurality of lines with one ofthe second plurality of terminals, and

means to prevent a line of the second plu- .;the: rece1vor is removedfrom the swltchrality from connecting with a terminal of the secondplurality in a particular group when an unanswered call from eitherplumatic association of.- the second jack and line I when an unansweredcall exists upon-the jack of the first line.

10. In a telephone system, the combination with three telephone lines,of. an answering jack and lamp permanently associated with one of saidlines, a pair of jacks and lamps and means to automatically associatethem with the other pair of lines, and means to prevent one of thelatter lines from being automatically associated with one of the jacksand lamps when either of the other second telephone line, a thirdtelephone line and a third lamp, and means whichmay automaticallyassociate said third line and said third lamp when a call exists uponthe'third telephone line, and means whereby the existence of anunanswered call upon either of the first telephone lines prevents theautomatic association of said third line and the third lamp.

12. In a telephone system, the combination with a telephone line, of ajack andlamp permanently associated therewith at the central oliice, asecond telephone line, a distributer switch, and a jack and lamp adaptedto be, associated with said line through the medium of said distributerswitch, a private conductor associated with said distributer switch,means actuated during the display of said first lamp toplace anelectrical condition upon said private conductor to pre vent thedistributer uswitch from connecting the second line with the secondjack.

13. Ina telephone system, the combination i with a pair of telephonelines, of an answer-- ing jack permanently associated with one ofsaidlines, a distributer switch for the latter line is closed at thesubstation and the private brush is registering with a grounded "privatecontact, and means associated with the first telephone line forgrounding one of theprivate contacts of said switch when hook atythesubstation of said line.

I 14L'In a telephone system, the combination with an undistributedtelephone line,

. automatically distributed and undistributed telephone lines, of meanswhereby unanswered calls on the undistributed telephone lines aliect theautomatic distribution of calls upon the distributed telephone lines.

16. In a telephone system, the combination with undistributed telephonelines, of

distributor switches, trunks extending from said distributer switches,and meanswhereby unanswered calls upon the undistributed telephone linesbar calls upon said trunks.

17. In a telephone system, the combination with a plurality of telephonelines, a plurality of trunk lines, automatic means for connecting any ofsaid telephone lines with any of said trunk lines, a cord circuit forextending said trunks into connection with desired ones of saidtelephone lines,

supervisory signals, one for each of said cord circuits, means todisplay said signals when the calling subscriber ofa connection seversthe telephone line at his substation, said means serving also to preventother telephone lines from being connected with other trunk circuitsduring the display of said signal, and means to efiace said signal.

18. In a telephone system, the combination with telephone lines, ofdistributer switches therefor, contacts of said switches extending tothe same operators position, an answering supervisory signal at saidoperators position displayed at the termination of a conversation toindicate that the connection should be taken down and means to preventcalls being distributed to an operators position after a conversationhas been terminated and before the connection has been taken down.

19. In a telephone exchange system, the combination with a plurality oftelephone lines upon some of which a large number of calls areoriginated, and upon others of which a small number of calls areoriginated, of a pluralityof operators positions at which the linesoriginating a small number of calls permanently terminate in connectingdevices so that each operator attends to substantilly an equal number oflines originating few calls, and automatic means for distributing thecalls received upon the lines originating a large number of calls beforethe various operators of the exchange who are not busy answering thepermanently terminated lines, whereby the work of the various operatorsis substantially equalized.

20. In a telephone exchange system, the combination with a switchboard,of a plurality of operators positions, a plurality of lines permanentlyterminated at each operators position, a second plurality of lines andmeans to automatically extend them to the various operators positions,the automatically extended lines being of sufiicient number so that whenthe calls received thereon are automatically distributed to non-busyoperators the work of all of the operators i substantially equalized;

21. In a telephone system, the combination with a division of aswitchboard, of telephone lines permanently terminating in answeringjacks at said division of the switchboard, trunk lines terminating atsaid division of the switchboard, an automatic switch for furthering aconnection between a calling line and one of said trunks, and

means at said division of the switchboard controlled by the condition ofsaid lines for preventing the automatic connection of said trunk with acalling line.

Signed by me at Rochester, county of Monroe, and State of New York, inthe presence of two witnesses.

HENRY P. CLAUSEN.

Witnesses: T

CHARLES E. HAGUE, TERESA A. BUCKLEY.

